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dc.contributorDepartment of Food Science and Nutritionen_US
dc.contributor.advisorFang, Kar-hei James (ABCT)en_US
dc.creatorYuen, Chue Ho-
dc.identifier.urihttps://theses.lib.polyu.edu.hk/handle/200/14209-
dc.languageEnglishen_US
dc.publisherHong Kong Polytechnic Universityen_US
dc.rightsAll rights reserveden_US
dc.titleImpact of microplastics on three life-history stages of stony coralsen_US
dcterms.abstractMicroplastic (MP) pollution is a growing threat to corals, particularly those are adjacent to the dense urban and industrial area. The current study aims to bridge a knowledge gap by examining life-stage-dependent responses of stony corals to microplastics, with emphasis on the early ontogenetic windows. Specifically, this work quantified the settlement, growth and photophysiological performance of Acropora tumida under controlled exposures that unravelled the roles of substrate conditioning and polymer identity.en_US
dcterms.abstractCoral planulae were reared in the laboratory and assigned to four treatments: Control, Symbiodinium (Zx; 900 000 cells L⁻¹), polystyrene (PS; 900 000 particles L⁻¹) and a Mix (900 000 cells L⁻¹ & 900 000 particles L⁻¹). Treatments were applied in parallel on biofilm-conditioned versus unconditioned ceramic tiles. In a second experiment, twelve-month-old juveniles and field-collected adult fragments were exposed for 30 days to polypropylene (PP; 10 mg L⁻¹), polyethylene terephthalate (PET; 10 mg L⁻¹) or natural sediment (10 mg L⁻¹); growth (surface area, polyp budding, buoyant weight) and photochemistry (Fo, Abs, Fv/Fm) were tracked with imaging-PAM fluorometry. Field surveys at four sites compared microplastics in Platygyra acuta skeletons with adjacent sediments in Mirs Bay.en_US
dcterms.abstractThe experimental findings were stage specific. Unconditioned tiles reduced larval settlement by 74–95% although post-settlement growth increased slightly (≈ 3–8%). On conditioned tiles, the Mix treatment suppressed settlement by 38%, indicating that PS-altered symbiont cues can nullify positive biofilm signals. In juveniles, PP significantly reduced tissue growth, polyp number and photochemical efficiency, whereas PET and sediment produced negligible effects. Adults remained mostly unaffected, with similar buoyant weight and Fv/Fm values to controls.en_US
dcterms.abstractField results showed that coral skeletons incorporated microplastic concentrations up to ten times higher than nearby sediments. The particle sizes were dominated by polyethylene fragments (30–100 µm) and reflecting stronger input from urban sources. Collectively, the findings indicated that microplastic effects depend on both coral life stage and polymer type. Comparing to Adults, juveniles are the more sensitive. These results highlight the need for reducing polymer-specific inputs and for conservation measures that prioritise the protection of early coral life stages in coastal waters with high microplastic loads.en_US
dcterms.extentxiv, 69 pages : color illustrationsen_US
dcterms.isPartOfPolyU Electronic Thesesen_US
dcterms.issued2025en_US
dcterms.educationalLevelM.Phil.en_US
dcterms.educationalLevelAll Masteren_US
dcterms.accessRightsopen accessen_US

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Please use this identifier to cite or link to this item: https://theses.lib.polyu.edu.hk/handle/200/14209